Circular piston machine



y 1967 E. FEZER ETAL 3,321,128

CIRCULAR PISTON MACHINE Filed Dec. 16, 1965 /nventors e ja/a( 7-1 ze Oskar S I'm 'n United States Patent O 3,321,128 CIRCULAR PISTON MACHINE Eberlard' Fezer, Essen-Bredeney, and Oskar Simon, Essen, Germany, assignors to Beteiligungsund Patentvewaltungsgesellschaft mit beschrankter Haftung, Essen, Germany Filed Dec. 16, 1965, Ser. No. 514317 Claims priority, application Germany, Dec. 19, 1964,

8 Claims. (Cl. 230-145) The present invention relates to a circular piston machine, especially internal combustion engine, having a stationary housing the inner surface of which has the cross-sectional shape of a multi-lobe epitrochoid. A machine of this type has vertical side walls which together with said housing confine an inner chamber through which in a direction perpendicular to said side walls there eX- tends a horizontal ecccntric shaft the eccenter of which rotata'bly supports a multi-corner piston. The end faces of said pisten are cquipped with axial scaling means comprising an annular oil seal and an end face seal.

Circular pisten machines of the above mentioned known type have the drawback that the scaling of the oil containing chambers by means of the heretofore customary annular oil seal is not fully satisfactory so that oil leakage is unavodable.

It is, therefore, an object of the present invention to provide a circular piston machine of the above mentoned general type which Will overcome the drawbacks referred to above.

It is another object of this invention to provide a circular piston machine of the general type set forth above, which will assure a proper seal between the side walls of the machine and the piston.

It is a further object of this invention to provide a circular piston machine as set forth in the preceding paragraph, which will comprse means adapted to prevent oil at the scaling surface between the pisten and the side walls of the machine from accumulating to any undesired extent.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

FIG. 1 shows a section through a portion of the oil seal between the pisten and the side walls of a machine according to the invention.

FIG. 2 is a view seen in the direction of the arrow A of FIG. 1.

FIG. 3 shows a view of an annular spring used in connection with the arrangement of FIG. l and seen in the direction of the arrow B of FIG. 1.

FIG. 4 is a cross section of a developed portion of the spring of FIG. 3.

The scaling arrangement according to the present invention is characterized primarily in that between the oil seal which is non-rotatably arranged in a side wall portion of the machine and the said side wall portion there is arranged an annular spring the effective diameter of which substantially equals the diameter of the inner edge of that scaling surface of the seal which slida'bly engages the adjacent pisten surface. The oil seal is provided with openings the outer contour of which extends from the inner edge of the scaling surface parallel to the ecccntric shaft or in a direction away therefrom. The location, size and number of said openings is so selected that the inner edge of the scaling surface at 'best engages the outer tangent of the respective two adjacent openings. The opcnings of said oil seal have their discharge mouth located 3,3Zl,l28 Patented May 23, 1967 on that side of said seal which is remote from said piston.

According to a further development of the present invention, it is suggested for purposes of improving the oil discharge from the scaling area, that the inner edge of the annular scaling surface of the oil seal is in axial direction followed by an inner surface which conically fiares with increasing distance from the inner edge of the annular scaling surface. As a result of this design, each point of the inner edge of the annular scaling surface has coordinatcd therewith an adjacent axis-remote point which means that from each point of the inner edge there exists a drop in outward direction.

According to a further improvement of the scaling eifect, it is suggested in conformity with the present invention that the outer edge of the annular scaling surface of the oil seal is in radial direction toward the outside followed 'by a wedge surface the radial extension of which is at least three times the radial extension of the scaling surface, said wedge surface forming an angle of approximately 5 with the surface engaged by said seal. In this way, during a radial relative movement between the annular scaling surface and the seal engaged thereby for scaling purposes, a wedging cifect is exerted upon any oil below the wedging surface whcreby the oil is returned to the space within the scaling surface. The inner edge of the scaling surface acts in the manner of a stripper and enhances this effect.

Referring now more specifically to the drawing, the side wall portion 11 of the circular piston machine, which ncidentally may, for instance, be of the design disclosed in U.S. Patent No. 3,208,666, has arranged therein an o l seal 2 according to the present invention. In radial direction, said oil seal 2 is elastically connected to the side wall portion 1 through the intervention of a scaling ring 3. Oil seal 2 has its annular scaling surface 4 in engagement with the contact surface 5 of circular pisten 6. The pressure at which the oil seal 2 is pressed in axal direction against the contact surface 5 is produced by an annular spring 7 which expediently is designed as an ondulated annular spring. The effective diameter d of spring 7 approximately equals the diameter d of the inner edge 8 of the annular scaling surface 4. Annular scaling surface 4 is in the direction toward the outside followed by a wedging surface 9 which forms an acute angle with the contact surface 5. Toward the inside from inner edge wedge 8, annular scaling surface 4 is followed by a conically fiaring inner surface 10.

Oil seal 2 is provided with a number of bores 11 which extend substantially parallel with regard to the ecccntric shaft of the machine, said bores being uniformly distributed over a pitch diameter d If the number of bores 11 is represented by the letter n and if the diameter of said bores is represented by the letter d the relationship between size and number of bores 11 is expressed by the formula so that the inner edge 8 of scaling surface 4 at best touches the outer tangent to the respective two adjacent bores 11.

Thus, while various types of material may be used for the oil seal 2 and the scaling ring 3, advantageously the oil seal is made of special grey iron and 'the scaling ring' is made of rubber.

As will be evident from the above, a scaling engagement according to the present invention furnishes a particularly good scaling eifect because the spring force of the annular spring which acts substantially directly upon the scaling surface and over the entire length thereof will, in cooperation with the oil seal which is rather elastic in view of the openings, bring about a proper engagement of the scaling surface with the respective adjacent contact surface of the piston, On the other hand, the arrangemcnt of the openings for the dischargc of the oil will assure that the oil collected within the range of the inner edge of the scaling surface will not unduly accumulate but will be discharged in any position of operation.

It is, of course, to be understood that the present invention is, by no means, limited to the particular arrangement shown in the drawing but also compriscs any modifications within the scope of the appcndcd claims.

What we claim is:

1. A circular piston machine, especially internal combustion engine having housing means including side wall means, an eccentric shaft rotatably supported by said housing means, and a multi-corner piston rotatably supported by said eccentric shaft, which comprises: annular oil-scaling means respectively arranged between said side wall means and the respective adjacent end faces of said piston and having one end face in scaling engagement with the respective adjacent end face of said piston, annular spring means intcrposed between each of said side wall means and the respective adjacent other end face of said scaling means while continuously urging said one end face of said scaling means into scaling engagement with the respective adjacent end face of said piston, said oil-scaling means being provided with a plurality of bores having their axes parallel to the longitudinal extension of said annular oil-scaling means, the position and the magnitude and the number of said bores being such that the inner edge of that portion of said one end face of said annular oil-scaling means at best touches the `outer tangcnt on two adjacent bores.

2. A circular piston machine according to claim 1, in which the effective diameter of said annular spring means approximately equals the inner diameter of said one end face of said annular oil-scaling means.

3. A circular piston machine according to claim 1, which includes an elastic scaling ring surrounding an outer peripheral portion of said annular oil-scaling means and interposed between and sealingly cngaging the outer peripheral portion of said annular oil-scaling means and an adjacent portion of said side wall.

4. A circular piston machine, especially internal combustion engine having housing means including side wall means, an ecccntric shaft rotatably supported by said housing means, and a multi-corner piston rotatably supported by said ecccntric shaft, which comprises: annular oil-scaling means rcspectivcly arranged between said side wall means and the respective adjacent end faces of said piston and having one end face in scaling cngagemcnt with the respective adjacent end face of said piston, an clastic scaling ring surrounding an outer pcripheral portion of said annular oil-scaling means and intcrposed between and scaling engaging the outer peripheral portion of said annular oil-scaling means and an adjacent portion of said side wall, annular spring means interposcd between each of said side wall means and the respective adjacent other end face of said scaling means while continuously urging said one end face of said scaling means into scaling cngagement with the respective adjacent end face of said piston, said oil-scaling means being provided with a plurality of bores having their aXcs parallel to the longitudinal extension of said annular oil-scaling means, said bores being cylindrical or flaring from said one end face of said oil-scaling means in a direction away therefrom and opening to said other end face, the position and the magnitude and the number of said bores being such that the inner edge of that portion of said one end face of said annular oil-scaling means at best touches the outer tangent an two adjacent bores.

5. A circular piston machine according to claim 1, in which said annular oil-scaling means adjacent its one end face has an inner pcripheral portion fiaring from said one end face in a direction away thcrefrom.

6. A circular piston machine according to claim 1, in which a radially inner portion of said one end face is in scaling engagemcnt with the respective end face of said piston while a radially outer portion of said scaling means adjacent to said radially inner portion is flaring radially outwardly in a direction away from the respective adjacent piston while confining thercwith an angle within the range of from 3 to 10.

7. A circular piston machine according to claim 6, in which the radially outwardly fiaring extension of said scaling means is at least three times the radial extension of said radially extending inner portion.

8. A circular piston machine according to claim 1, in which the inner diameter of said annular oil-scaling means at its piston engaging surface is expressed by the formula cl =d c-os 180/n+d in which d indicates said inner diameter, n indicates the number of said bores, d indicates the diameter of each of said bores and d indicates the pitch circle on which said bores are located.

References Cited by the Examincr UNITED STATES PATENTS 3,171,590 3/1965 Bcntele et al 123--8 X 3,176,91O 4/1965 Bcntele 230-145 ROBERT M. WALKER, P''mary Examner. 

1. A CIRCULAR PISTON MACHINE, ESPECIALLY INTERNAL COMBUSTION ENGINE HAVING HOUSING MEANS INCLUDING SIDE WALL MEANS, AN ECCENTRIC SHAFT ROTATABLY SUPPORTED BY SAID HOUSING MEANS, AND A MULTI-CORNER PISTON ROTATABLY SUPPORTED BY SAID ECCENTRIC SHAFT, WHICH COMPRISES: ANNULAR OIL-SEALING MEANS RESPECTIVELY ARRANGED BETWEEN SAID SIDE WALL MEANS AND THE RESPECTIVE ARRANGED BETWEEN SAID SIDE PISTON AND HAVING ONE END FACE IN SEALING ENGAGEMENT WITH THE RESPECTIVE ADJACENT END FACE OF SAID PISTON, ANNULAR SPRING MEANS INTERPOSED BETWEEN EACH OF SAID SIDE WALL MEANS AND THE RESPECTIVE ADSJACENT OTHER END FACE OF SAID SEALING MEANS WHILE CONTINUOUSLY URGING SAID ONE END FACE OF SAID SEALING MEANS INTO SEALING ENGAGEMENT WITH THE RESPECTIVE ADJACENT END FACE OF SAID PISTON, SAID OIL-SEALING MEANS BEING PROVIDED WITH A PLURALITY OF BORES HAVING THEIR AXES PARALLEL TO THE LONGITUDINAL EXTENSION OF SAID ANNULAR OIL-SEALING MEANS, THE POSITION AND THE MAGNITUDE AND THE NUMBER OF SAID BORES BEING SUCH THAT THE INNER EDGE OF THAT PORTION OF SAID ONE END FACE OF SAID ANNULAR OIL-SEALING MEANS AT BEST TOUCHES THE OUTER TANGENT ON TWO ADJACENT BORES. 